brenthutch 388 #1 Posted February 12, 2022 While we may have our political differences, I will gladly acknowledge the expertise of BillV and even that adorable curmudgeon Kallend in the field of things electric. Therefore, I humbly beseech your counsel on the efficacy, or lack thereof, on lithium iron phosphate vs lead acid batteries. (for use on a trolling motor) Quote Share this post Link to post Share on other sites
JoeWeber 2,316 #2 February 12, 2022 1 hour ago, brenthutch said: While we may have our political differences, I will gladly acknowledge the expertise of BillV and even that adorable curmudgeon Kallend in the field of things electric. Therefore, I humbly beseech your counsel on the efficacy, or lack thereof, on lithium iron phosphate vs lead acid batteries. (for use on a trolling motor) Well, you concede to the reality of electric fields so we're making progress. I run 20kW of lithium batteries on my boat. There is no comparison. I'm also looking for a lithium motorcycle battery for the dinghy, but things are scare here. Just go lithium and don't look back. Seriously. Quote Share this post Link to post Share on other sites
brenthutch 388 #3 February 12, 2022 1 hour ago, JoeWeber said: Well, you concede to the reality of electric fields so we're making progress. I run 20kW of lithium batteries on my boat. There is no comparison. I'm also looking for a lithium motorcycle battery for the dinghy, but things are scare here. Just go lithium and don't look back. Seriously. They claim they are 4x as powerful yet cost 5x. Looking for other variables to justify the difference for my application. Quote Share this post Link to post Share on other sites
billvon 2,408 #4 February 12, 2022 3 hours ago, brenthutch said: on lithium iron phosphate vs lead acid batteries. (for use on a trolling motor) The only two benefits of lead acid are lower cost and safer operation at lower temperatures. Lead acids will operate at almost any temperature. At low temperatures they will not freeze down to about -70C - AS LONG AS THEY ARE CHARGED. (Critical provision there.) As they discharge they will freeze at a higher temperature. When they are completely discharged they will freeze around 0C - and freezing will destroy them. They will not give much power at low temperatures but they will give a little, and charging them will raise their temperatures. They have to be temperature compensated - they need higher voltages at lower temperatures for charging and the charger must handle that automatically. Most (good) dedicated lead acid chargers do. Lead acids can really only be used down to 50% if you want them to last a long time and must be stored either fully charged or close to it. LFP are much lighter per kwhr, provide more power per pound and are much easier to charge - they just need a constant voltage of about 3.6 volts per cell. 12V LFP's are made of four cells so that's 14.4 volts, which is close enough to standard 12V lead acids that they will usually work in the same applications. Their two drawbacks are cost and temperature. They used to be 4x as expensive as lead acid for the same energy, but are now down to about 2-3x. And since you can discharge them to 100%, they end up almost the same price per kwhr of useful energy. Their one Achilles heel is temperature. They cannot be charged below 0C and cannot be used below -20C. Doing so will damage the battery. Many better batteries now include cell heaters, so as long as they are not being relied on for long duration operation (days) at very low temperatures you are generally OK down to -40C or so. Quote Share this post Link to post Share on other sites
brenthutch 388 #5 February 12, 2022 Thank you Bill and Joe, looks like LFP for me. Quote Share this post Link to post Share on other sites
Phil1111 913 #6 February 12, 2022 I was just looking at this same equation this week. Cabelas has this "sale" on a what is not much more than a lantern battery. But I've been studying this guy's You-tube videos on building your own. He has a kw lot of subscribers. Quote Share this post Link to post Share on other sites
JoeWeber 2,316 #7 February 12, 2022 1 hour ago, brenthutch said: Thank you Bill and Joe, looks like LFP for me. OK, Buddy! Who are you and what did you do with Brent? Brent, wherever you are just hang in there, we're on the way. 1 Quote Share this post Link to post Share on other sites
brenthutch 388 #8 February 12, 2022 2 hours ago, Phil1111 said: I was just looking at this same equation this week. Cabelas has this "sale" on a what is not much more than a lantern battery. But I've been studying this guy's You-tube videos on building your own. He has a kw lot of subscribers. 12V 100Ah version from the same manufacturer is more than $1000. Quote Share this post Link to post Share on other sites
brenthutch 388 #9 February 12, 2022 1 hour ago, JoeWeber said: OK, Buddy! Who are you and what did you do with Brent? Brent, wherever you are just hang in there, we're on the way. LOL Quote Share this post Link to post Share on other sites
headoverheels 291 #10 February 12, 2022 9 hours ago, brenthutch said: Thank you Bill and Joe, looks like LFP for me. They always help with your trolling. 1 Quote Share this post Link to post Share on other sites
brenthutch 388 #11 February 12, 2022 10 minutes ago, headoverheels said: They always help with your trolling. Just because you don’t like the content doesn’t make it a troll. Case in point https://link.springer.com/article/10.1140/epjp/s13360-021-02243-9 Quote Share this post Link to post Share on other sites
JoeWeber 2,316 #12 February 12, 2022 (edited) 1 hour ago, headoverheels said: They always help with your trolling. Irritating, annoying and repetitive in the face of better evidence does not a troll make. One night I woke up at 3:00AM in a two dollar dive hole of a room with a dip toilet on the second floor of the train station in Jaipur, India. On the platform below an army brass band was beating out what I can only guess was supposed onto be a coherent song. For the most part it made no sense and just made my head hurt. That didn't make them trolls, just true believers like Brent. Be nice. Unlike some, when Brent is gone we'll miss him. Edited February 12, 2022 by JoeWeber 1 Quote Share this post Link to post Share on other sites
headoverheels 291 #13 February 13, 2022 2 hours ago, brenthutch said: Just because you don’t like the content doesn’t make it a troll. Case in point https://link.springer.com/article/10.1140/epjp/s13360-021-02243-9 You are the one that started this thread about your trolling battery. Now, you have injected a link to an unrelated topic -- a different type of troll. Quote Share this post Link to post Share on other sites
brenthutch 388 #14 February 13, 2022 25 minutes ago, headoverheels said: You are the one that started this thread about your trolling battery. Now, you have injected a link to an unrelated topic -- a different type of troll. Sorry, I missed the nuance of your reply Quote Share this post Link to post Share on other sites
headoverheels 291 #15 February 13, 2022 9 minutes ago, brenthutch said: Sorry, I missed the nuance of your reply After posting, I realized that a smiley face would have added clarity. Quote Share this post Link to post Share on other sites
